[jira] [Updated] (YARN-2327) YARN should warn about nodes with poor clock synchronization
[ https://issues.apache.org/jira/browse/YARN-2327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Colin Patrick McCabe updated YARN-2327: --- Description: YARN should warn about nodes with poor clock synchronization. YARN statistics rely on approximate clock synchronization in a few cases (see YARN-2251), but we currently don't warn if this assumption is violated. was: As a distributed system, a hadoop cluster wants the clock on all the participating hosts synchronized. Otherwise, some problems might happen. For example, in YARN-2251, due to the clock on the host for the task container falls behind that on the host of the AM container, the computed elapsed time (the diff between the timestamps produced on two hosts) becomes negative. In YARN-2251, we tried to mask the negative elapsed time. However, we should seek for a decent long term solution, such as providing mechanism to do and check clock synchronization. > YARN should warn about nodes with poor clock synchronization > > > Key: YARN-2327 > URL: https://issues.apache.org/jira/browse/YARN-2327 > Project: Hadoop YARN > Issue Type: Bug >Reporter: Zhijie Shen > > YARN should warn about nodes with poor clock synchronization. > YARN statistics rely on approximate clock synchronization in a few cases (see > YARN-2251), but we currently don't warn if this assumption is violated. -- This message was sent by Atlassian JIRA (v6.2#6252)
[jira] [Updated] (YARN-2327) YARN should warn about nodes with poor clock synchronization
[ https://issues.apache.org/jira/browse/YARN-2327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Colin Patrick McCabe updated YARN-2327: --- Description: YARN should warn about nodes with poor clock synchronization. YARN relies on approximate clock synchronization to report certain elapsed time statistics (see YARN-2251), but we currently don't warn if this assumption is violated. was: YARN should warn about nodes with poor clock synchronization. YARN statistics rely on approximate clock synchronization in a few cases (see YARN-2251), but we currently don't warn if this assumption is violated. > YARN should warn about nodes with poor clock synchronization > > > Key: YARN-2327 > URL: https://issues.apache.org/jira/browse/YARN-2327 > Project: Hadoop YARN > Issue Type: Bug >Reporter: Zhijie Shen > > YARN should warn about nodes with poor clock synchronization. > YARN relies on approximate clock synchronization to report certain elapsed > time statistics (see YARN-2251), but we currently don't warn if this > assumption is violated. -- This message was sent by Atlassian JIRA (v6.2#6252)
[jira] [Updated] (YARN-2327) YARN should warn about nodes with poor clock synchronization
[ https://issues.apache.org/jira/browse/YARN-2327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Colin Patrick McCabe updated YARN-2327: --- Summary: YARN should warn about nodes with poor clock synchronization (was: A hadoop cluster needs clock synchronization) > YARN should warn about nodes with poor clock synchronization > > > Key: YARN-2327 > URL: https://issues.apache.org/jira/browse/YARN-2327 > Project: Hadoop YARN > Issue Type: Bug >Reporter: Zhijie Shen > > As a distributed system, a hadoop cluster wants the clock on all the > participating hosts synchronized. Otherwise, some problems might happen. For > example, in YARN-2251, due to the clock on the host for the task container > falls behind that on the host of the AM container, the computed elapsed time > (the diff between the timestamps produced on two hosts) becomes negative. > In YARN-2251, we tried to mask the negative elapsed time. However, we should > seek for a decent long term solution, such as providing mechanism to do and > check clock synchronization. -- This message was sent by Atlassian JIRA (v6.2#6252)
